Generally, a seat for a motor vehicle, which is configured of a seat cushion and a seat back to maintain a boarding attitude of a passenger, is provided on a driver seat and a passenger seat and is divided into a separator type seat on which only one person may be seated and a bench type seat provided behind the driver seat and the passenger seat so that several persons may be simultaneously seated thereon.
The separator type seat provided at the driver seat and the passenger seat may be adjusted in accordance with a body type of a driver and a passenger so that the driver and the passenger may maintain an attitude appropriate for driving, and a seat back serving as a back support so that the passenger may take a rest is provided with a reclining apparatus adjusting an angle forward or backward.
The bench type seat provided at the rear of the motor vehicle is provided with a seat back latch allowing the seat back to be folded forward in order to mount a load having a large volume or a long length in a trunk. Recently, a technology of adjusting an inclination of the seat back to increase an amount of load without folding the seat back has been known.
In the seat back latch according to the related art shown in FIG. 1, when a lever 51 is pulled in an arrow direction C, a first link 52 rotates while being pulled, a second link 53 formed integrally with the first link 52 also rotates while forming a rotation trajectory as shown by an arrow B around a hinge 54, and a latch tooth 57 connected to the second link 53 and a pin 55 through a long hole 56 rotates according to a trajectory of an arrow A around a hinge axis 58, such that a striker 60 engaged with a tooth 59 of the latch tooth 57 is unlocked from the latch tooth 57, thereby making it possible to change a seat back support angle.
In addition, when a state in which the lever 51 is pulled is released, the latch tooth 57 and the first and second links 52 and 53 return to their original states by elastic force of a return spring 61, such that the striker 60 is again received and locked in the tooth 59.
In the seat back latch according to the related art, the striker 60 is locked to and supported by the tooth 59 of the latch tooth 57. However, a connection portion between the latch tooth 57 and the first and second links 52 and 53 is weak, such that a locking operation is unreliable and there is a risk that a state in which the striker 60 is locked will be arbitrarily released.